The phase separation due to A-site-cation size mismatch in La0.5Ca0.5-xBaxMnO3

2001 ◽  
Vol 13 (8) ◽  
pp. 1627-1639 ◽  
Author(s):  
Hironori Wakai
Keyword(s):  
Phase Separation ◽  
Size Mismatch ◽  
A Site ◽  
Cation Size

scholarly journals Structural and Electrical Properties of Ca2+ Doped LaFeO3: The Effect of A-site Cation Size Mismatch

2020 ◽  
Vol 10 (2) ◽  
pp. 5538-5546
Author(s):  
A. E. Irmak
Keyword(s):  
Crystal Structure ◽  
Sol Gel ◽  
Charge Ordering ◽  
Room Temperature Resistivity ◽  
Size Mismatch ◽  
Ca Doping ◽  
Average Size ◽  
A Site ◽  
Cation Size ◽  
Small Polarons

In this study, nanosized La1-xCaxFeO3 (0.00≤x≤0.40) compounds prepared via sol-gel method followed by heat treatment at 1100oC for 24 hours are studied. Crystal structure, microstructure, surface morphology and temperature-dependent resistivity of the samples are investigated. TEM investigation reveals nanoparticles with an average size of 35nm produced from the sol-gel process. The crystal structure of the compounds belongs to an orthorhombically distorted perovskite structure with Pbnm space group. Lattice distortion and cation size mismatch increase with an increase in Ca and particle and grain growth are suppressed by Ca doping. Electrical conduction is explained via thermally activated hopping of small polarons. Unit cell volume, charge ordering temperature, and activation energy for small polarons decrease linearly with an increase in cation size mismatch. Room temperature resistivity decreases with Ca doping and gets its minimum value for 30% Ca at which the orthorhombic distortion is maximum.

The role of A-site cation size mismatch in tune the catalytic activity and durability of double perovskite oxides

2020 ◽  
Vol 270 ◽  
pp. 118868 ◽  
Author(s):  
Shengli Pang ◽  
Jie Xu ◽  
Yanjing Su ◽  
Gongmei Yang ◽  
Meng Zhu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Double Perovskite ◽  
Perovskite Oxides ◽  
Size Mismatch ◽  
A Site ◽  
Cation Size

Effect of A-site cation size mismatch on charge ordering behavior in (La1−xYx)0.5(Ca1−ySry)0.5MnO3

2001 ◽  
Vol 90 (1) ◽  
pp. 488-492 ◽  
Author(s):  
Y. Q. Wang ◽  
Ian Maclaren ◽  
X. F. Duan ◽  
Z. H. Wang ◽  
B. G. Shen
Keyword(s):  
Charge Ordering ◽  
Size Mismatch ◽  
A Site ◽  
Cation Size

scholarly journals Effect of synthesis conditions on electrical and catalytical properties of perovskites with high value of A-site cation size mismatch

2016 ◽  
Vol 41 (43) ◽  
pp. 19810-19818 ◽  
Author(s):  
K. Vidal ◽  
A. Larrañaga ◽  
A. Morán-Ruiz ◽  
A.T. Aguayo ◽  
M.A. Laguna-Bercero ◽  
...  
Keyword(s):  
Size Mismatch ◽  
Synthesis Conditions ◽  
A Site ◽  
Cation Size

Cation-size mismatch and interface stabilization for efficient NiOx-based inverted perovskite solar cells with 21.9% efficiency

Nano Energy ◽  
2021 ◽  
pp. 106285
Author(s):  
Yousheng Wang ◽  
Hui Ju ◽  
Tahmineh Mahmoudi ◽  
Chong Liu ◽  
Cuiling Zhang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Perovskite Solar Cells ◽  
Size Mismatch ◽  
Cation Size

Hydrothermal synthesis of ABi2Ta2O9Aurivillius phase: A comparative study of A-site cation size on structure, dielectric, optical properties

2021 ◽  
Author(s):  
Ilona Bella ◽  
Tio Putra Wendari ◽  
Novesar Jamarun ◽  
Nandang Mufti ◽  
Zulhadjri
Keyword(s):  
Xrd Analysis ◽  
Aurivillius Phase ◽  
Hydrothermal Route ◽  
Orthorhombic Crystal ◽  
Ionic Radii ◽  
Aurivillius Phases ◽  
Orthorhombic Crystal Structure ◽  
A Site ◽  
Cation Size ◽  
Ferroelectric Transition Temperature

In this study, the double-layered Aurivillius phases CaBi2Ta2O9 (CBT) and PbBi2Ta2O9 (PBT) were prepared through a hydrothermal route with NaOH as a mineralizer. XRD analysis confirmed that the CBT and PBT compounds were successfully formed and adopted an orthorhombic crystal structure with an [Formula: see text]21am symmetry. Le Bail refinements of XRD data indicated that the unit cell volume of CBT was smaller than PBT and is associated with the smaller ionic radius of Ca[Formula: see text] compared to Pb[Formula: see text]. The surface morphology of both samples, as determined using SEM, demonstrated plate-like grains with anisotropic grain growth. It was found that the different ionic radii of [Formula: see text]-site cations (Ca[Formula: see text] and Pb[Formula: see text] strongly affected the structural, optical and electrical properties of the Aurivillius phase. The occupation of smaller Ca[Formula: see text] cations induced a higher structural distortion, which resulted in higher bandgap ([Formula: see text] energy and ferroelectric transition temperature ([Formula: see text] of CBT, compared to those of PBT.

Ionic conductivity and mixed-ion effect in mixed alkali metaphosphate glasses

2017 ◽  
Vol 19 (9) ◽  
pp. 6594-6600 ◽  
Author(s):  
Jefferson Esquina Tsuchida ◽  
Fabio Aparecido Ferri ◽  
Paulo Sergio Pizani ◽  
Ana Candida Martins Rodrigues ◽  
Swarup Kundu ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Experimental Evidence ◽  
Natural Consequence ◽  
Size Mismatch ◽  
Mixed Alkali ◽  
Cation Size

Experimental evidence has confirmed that the mixed-ion effect (MIE) can be explained as a natural consequence of random ion mixing and that the cation size mismatch is not the only factor that determines the intensity of MIE.

Strain driven structural phase transformations in dysprosium doped BiFeO3 ceramics

2014 ◽  
Vol 2 (17) ◽  
pp. 3345-3360 ◽  
Author(s):  
Robert C. Lennox ◽  
Mark C. Price ◽  
William Jamieson ◽  
Marek Jura ◽  
Aziz Daoud-Aladine ◽  
...  
Keyword(s):  
Phase Transformations ◽  
Structural Phase ◽  
Size Mismatch ◽  
Strain Effects ◽  
Large Size ◽  
A Site ◽  
Chemical Strain ◽  
Structural Phase Transformations

Chemical strain effects arising from the large size mismatch between the two A-site cations results in a lowering of the symmetry from polar R3c to a polar Cc in Bi0.95Dy0.05FeO3.

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